Conventionally, humidity control apparatuses are known, which include liquid absorbent such as a lithium chloride solution, and moisture permeable membranes not allowing the liquid absorbent to permeate but allowing only water vapor to permeate.
For example, Patent Document 1 shows a humidity control apparatus including a circuit in which liquid absorbent circulates, and a refrigerating apparatus performing refrigeration cycles (see, e.g., paragraphs [0031]-[0033] and FIG. 8 of Patent Document 1). This humidity control apparatus includes a dehumidification section and a regeneration section. In the dehumidification section, a dehumidification air passage including a fan 11 is separated from the passage of the liquid absorbent by a moisture permeable membrane 13. On the other hand, in the regeneration section, a regeneration air passage including a fan 10 is separated from the passage of the liquid absorbent by the moisture permeable membrane 13. In addition, in this humidity control apparatus, a condenser 18 of the refrigerating apparatus is disposed in the passage which allows the liquid absorbent to flow from the dehumidification section to the regeneration section. An evaporator 20 of the refrigerating apparatus is disposed in the passage which allows the liquid absorbent to flow from the regeneration section to the dehumidification section.
In the humidity control apparatus of Patent Document 1, the liquid absorbent circulates between the dehumidification section and the regeneration section. The liquid absorbent, which has absorbed the water vapor in the air in the dehumidification section, is heated in the condenser 18, and then flows into the regeneration section. In the regeneration section, the liquid absorbent releases the water vapor to the air. The liquid absorbent flowing from the regeneration section is cooled in the evaporator 20, and then flows into the dehumidification section to absorb the moisture from the air again.
Patent Document 2 shows a humidity control element 7 for dehumidifying air using a moisture permeable sheet 10 and liquid absorbent (see, e.g., paragraphs [0034], [0035], [0042], and [0051] and FIGS. 1-5 of Patent Document 2). This humidity control element 7 includes a moisture permeable element 5 and a heat source body 6. In the moisture permeable element 5, a porous member 12 is encapsulated in a bag including the moisture permeable sheet 10 on one surface, and a metal sheet 11 on the other surface. The heat source body 6 includes a pipe 15 through which refrigerant flows, and a flat plate-like fin member 16 attached to the pipe 15. In the humidity control element 7, the metal sheet 11 of the moisture permeable element 5 is attached to the fin member 16 of the heat source body 6.
In the humidity control element 7 according to Patent Document 2, when the liquid absorbent permeates the porous member 12, the water vapor, which has permeated through the moisture permeable sheet 10, is absorbed by the liquid absorbent. As a result, the air flowing outside the moisture permeable sheet 10 is dehumidified. At this time, the liquid absorbent held by the porous member 12 is cooled by the refrigerant flowing through the pipe 15.
Patent Document 3 shows an evaporative cooler utilizing a moisture permeable membrane. In this evaporative cooler, the passage of inflow air, the passage of liquid desiccant (liquid absorbent), the passage of coolant (water), and the passage of discharged air are stacked one on another. The passage of the inflow air and the passage of the liquid desiccant are separated by a moisture permeable membrane 112. The passage of the coolant and the passage of the discharged air are separated by a moisture permeable membrane 118. Furthermore, the passage of the liquid desiccant and the passage of the coolant are separated by a separation wall 114 which does not allow water vapor to permeate. The inflow air is dehumidified by the liquid desiccant. The water, which is coolant, is partially evaporated and released to the discharged air, thereby reducing the temperature of the discharged air. The liquid desiccant and the coolant exchange heat.
Patent Document 4 shows a humidity control apparatus including adsorbent such as zeolite, and a refrigerating apparatus. In an adsorption unit 4 included in the humidity control apparatus, a refrigerant pipe 21 is disposed in a mesh container 22 filled with adsorbent 23, and refrigerant flowing through the refrigerant pipe 21 heats or cools the adsorbent 23 (see, paragraphs [0029] and [0030] and FIG. 3 of the cited document 4).